The field of the invention is systems and methods for processing a flat media workpiece.
Various systems and methods have been used in the past for processing flat media workpieces, both individually and in batches or groups of workpieces. In the semiconductor device manufacturing industry, the workpieces are typically flat, thin and round disks or wafers, often made of a semiconductor material. Depending on the manufacturing steps being performed, various liquids, gases or vapors may be applied or sprayed onto the workpiece, while the workpiece is spinning. In some manufacturing steps, process liquids or gases are applied to the bottom surface of a spinning wafer via spray nozzles. Immersion processing has been separately performed by immersing wafers into tanks of liquid process chemicals, with the tanks optionally including a sonic energy source.
While these types of systems and methods have performed well in the past, there remains a need for systems and methods having improved performance characteristics.
Accordingly, it is an object of the invention to provide an improved system and an improved method for processing wafers or other flat media workpieces.
In a first aspect of the invention, a sonic workpiece processing system has a workpiece holder in a head. A motor is provided for spinning the workpiece held in the workpiece holder. A base has a process bowl or chamber including a sonic energy source, such as a megasonic transducer. A liquid and/or gas chemical applicator, such as a nozzle, is provided on a swing arm. A head lifter is adapted to move the workpiece into an immersion position, a rinse position, and a dry position. The workpiece is sequentially moved into the three positions by either lifting the head, or lowering the base. Versatile workpiece processing is provided, as the system allows for immersion processing, sonic processing, and spin processing, rinsing and drying, within a single system, and without the need to move the workpiece between systems.
In a second aspect, one or more quick drain valves are provided in the bowl, to rapidly drain liquid after immersion processing. As a result, processing of the workpiece is expedited and risk of contamination from used immersion liquid, is reduced.
In a third aspect, in a method for processing a workpiece, the workpiece is immersed in a liquid bath. Sonic energy is provided into the bath, while the workpiece is stationary, or spinning. The workpiece is withdrawn from the bath and rinsed. The rinsing is preferably performed by spinning the workpiece while spraying rinsing liquid onto the workpiece. The bath liquid is advantageously quickly drained before the rinsing step is completed. The workpiece is then moved to a drying position. A spray arm sprays or applies a drying fluid, such as IPA or nitrogen, to the workpiece, while the workpiece is spinning. The spray arm preferably reciprocates back and forth underneath the spinning workpiece, to allow for more uniform application of the drying fluid to all areas of the bottom surface of the workpiece. The method provides for expedited and efficient workpiece processing, with both immersion, sonic and spray/spin capabilities, resulting in a wide range of applications.
Other objects, features and advantages will also be apparent from the following detailed description and drawings. The invention resides as well in subsystems of the apparatus and methods described.